This application requests funds for state-of-the-art laser capture microdissection (LCM) equipment, specifically, a Pixcell lle LCM instrument (Arcturus Engineering, Mountain View, CA). Laser capture microdissection is a powerful new technology for study of in vivo tissues. It permits isolation of particular cell types, or cells from particular locations, from complex or heterogeneous tissues. Subsequently, nucleic acids or proteins can be extracted from the microdissected cells, and analyzed. This institution's only LCM apparatus is the prototypic and outdated Pixcell I, purchased in 1998. It has been heavily and productively used, resulting in publications, funding, and promising preliminary data. However, the instrument is obsolete: the beam-width is wide, the software does not interface with current programs and as of 9/03 the company no longer provides maintenance or support for this model. Demand is strong for an up-to-date instrument with better optics and software, which is capable of dissecting smaller areas and fluorescent-labeled cells. Therefore, the Pixcell's current major users, along with additional investigators, request support for an updated LCM instrument. The major users are productive, NIH-funded investigators, experienced with prototype equipment, for whose biomedical research the ability to isolate small homogeneous cell populations is fundamental. The institution, recognizing the need for this instrument has committed support to maintain this critical research resource. This constellation seems ideally suited to the purposes of the NCRR SIG program.